Power-transmitting device for engines.



No. 684,883. Patented Oct. 22, |90l.

E. THOMSON.

POWER TBAVNSMITTING DEVICE FOR ENGINES.

(Application filed Nov. 16, 1900.)

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NITED STATES PATENT OFFICE.

LIHU THOMSON, OF SWAMPSOOTT, MASSACHUSETTS.

POWER-TRANSMITTING DEVICE FOR ENGINES.

rSIECIIFEIGA'JJIOIBT forming part of Letters Patent No. 684,883, datedOctober 22, 1901.

Application filed November 16, 1900. Serial No. 36,688. (No model.)

To @ZZ whom t may concern,.-

Be it known that I, ELIHU THOMSON, a citizen of the United States,residing at Swampscott, county of Essex, State of Massachusetts, haveinvented certain new and useful Improvements in Power-TransmittiugDevices for Engines, (Oase No. 1,850,) of which the following is aspecification.

In automobiles intended for ordinary road use there are times when it isdesirable to coast. This may be owing to a gradient or to a desire onthe part of the operator to save energy. In vehicles propelled by steamor com pressed gas as ordinarily constructed the engine is connected tothe driving wheel or wheels by suitable mechanical connectionssuch, forexample, as worm or spur gearing or sprockets and chain. Thisconstruction is satisfactory when the vehicle is being propelled by theengine; but when the power is out oi and the driving wheel or wheelstend to drive the engine there is a considerable friction loss owing tothe pistons being dragged back and forth within the cylinders.

The object of the present invention is to overcome the objection abovepointed out and to provide means for automatically disconnecting thepistons from the driving mechanism or otherwise render the saidmechanism inoperative whenever the vehicle is coasting, or, in otherwords, whenever the driven element tends to drive the engine, and thiswithout the use of a separate manual controlling device or withoutthought on the part of the operator.

In the accompanying drawings,which illustrate an embodiment of myinvention, Figure l is a longitudinal section of a trunk-engine. Fig. 2is also a longitudinal section of a trunken gine, showing the crankworking independent of the pistons, which occurs when the vehicle-wheelsare driving and the engineis not drawing on the source of energy. Fig. 3represents a four-cylinder engine arranged to impart motion to thedriving-wheels. Fig. 4 is a transverse section of the gear-drivingmechanism, and Fig. 5 is a partial side View and section of the same.

In the drawings, A represents one cylinder of a trunk-engine, and B thesecond cylinder.

These cylinders are oppositely disposed, and

` mounted for movement within the cylinders are pistons O and D. Theengine is designed to receive hot high-pressure steam or hot compressedgases, which lis admitted through suitable ports. The pistons'aresingle-acting and are so arranged that at the end of each stroke theexhaust-ports E will be uncovered. If desired, other forms of yvalvemechanism may be employed-for example, that shown in connection withFig. S-Wherein puppetvalves are used, which are actuated throughmeansdriven by the main shaft of the engine, or the same ports may be usedfor both admission and exhaust. The pistons C and D work throughconnecting-rods G and H on a common crank F, which is carried'by themain shaft of the engine. These rods are made of two parts which aremovable with respect to each other. On account of simplicity `theconnecting-rods are shown as being composed of a rod and tube, theformer working within the latter. I do not desire to be understood aslimiting myself, however, to the telescoping structure shown-that is tosay, surrounding one part with another Within which it is capable ofmoving-since the invention broadly contemplates a twopart looseconnection between each piston and the crank-shaft regardless of itsprecise construction. Considering the specific construction of theconnection-rods, the rod-like portion is pivotally secured to thepiston, while the tubular portion is connected to the wrist-pin I in theusual manner. Near the inner end ot' each tube is a small opening J, andthis, together with the piston and cylinder like structure of theconnecting-rods, constitutes a dash-pot for taking up the thrust of theparts and preventing the metallic shocks and hammering which wouldotherwise occur in placing the parts in operative relation. The openingJ also serves to break the vacuum which would exist if the parts of therod moved vindependent of each other.

' In Fig. l the parts are shown in one of the positions occupied by themwhen the engine is in operation. In the figure the right-hand piston isin a position to receive steam, while the left-hand piston is shown asuncovering the exhaust-ports E. Steam or other fluid on being admittedto the right-hand cylinder through a throttle-valve and inlet-portforces the piston to the left. Shortly after the start roo the left-handpiston will close the exhaustports, and as the movement continues therewill be a compression more or less great of the gas or mixture in thecylinder. The compressed charge in the cylinder will hold the left-handpiston in its proper position with respect to the other. At the end ofthe stroke the right-hand piston uncovers or otherwise opens theexhaust-port and the ports are in a position to receive steam or gas,but from the opposite end.

Assuming now that the engine-shaft is connected by a suitable mechanicalconnection with the driving-wheels of a vehicle or to some other devicewhich at times is driven and at other times acts as a driving member andthat power is cut off from the engine and the wheels or other mechanismbegin to act as driving members, the pistons will be forced to the backends of the cylinders by the connecting-rods, due to the rotation of theengine-shaft, and will remain until they again begin to drive the mainshaft. This is illustrated in Fig. 2. As the crank-shaft turns thetubular portions of the connectingrods will slide back and forth on therods and the friction loss will be comparatively small,whereas withsolid connecting-rods and pistons united thereto, as is the ordinaryconstruction, there is a large relative friction loss due to -thepistons being pulled back and forth in the cylinder, which loss it isthe aim of my invention to avoid.

Assuming that the parts are in the position shown in Fig. 2 and that itis desired to start up the engine, the admission-valves being properlyset, when one of the connecting-rods is shortened to the limit, or, inother words, the rod and piston are in the position shown in theright-hand end of Fig. I, steam will be admitted through a suitablethrottle-Valve to the right-hand cylinder. This will start the engineinto operation, and when the crank occupies a position diametricallyopposite that of Fig. l the left-hand piston will be in an operativeposition and the proper valve will open and admit steam. During theinterval above referred to the piston and cylinder like structure of theconnecting-rods will act as a dash-pot or check and take up the thrustbetween the left-hand piston and its connecting-rod. After thistheoperation is the same as an ordinary two-cylinder engine.

In Fig. 3 my invention is shown in connection withafour-cylindersingle-actin g engine, each piston being provided with atwo-part connecting-rod, the parts of which are movable with respect toeach other when the vehicle-wheels K tend to propel the engine, butwhich remain in fixed relation when the engine is receiving` steam orcompressed gas and is propelling the vehicle. The admission of steam orother duid to the cylinder is controlled by a series of puppet-valves L,which are actuated by cams M on the engine-shaft, and the exhaust iscontrolled by the exhaustes4,sss

ing two universal connections R, so that freedom of action is assured.The action of the driving mechanism being the saine as described inconnection with Figs. l and 2, the only difference being that fourpistons are used instead of two, further description is unnecessary.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. A connecting-rod for an engine, composed of two sections which arefree to slide with respect to each other.

2. In a single-acting engine, a cylinder, a piston, a shaft, and aconnecting-rod between the piston and the shaft, composed of at leasttwo sections free to slide with respect to cach other.

3. In an engine, the combination of a divided connecting-rod, the partsbeing free to move with respect to each other, with means for guidingthe parts in their movements.

4:. In an engine, the combination of a cylinder, a piston, and a dividedconnecting-rod, the parts of which are telescoped on each other and arefree to move.

5. In an engine, the combination of a cylinder, a piston, a crank, aconnecting-rod between the piston and cylinder, composed of portionsfree to slide with respect to each other, and a device acting to cushionthe movements of the parts of the connecting-rod.

6. In an engine, the combination of a cylinder, a piston, a crank, aconnecting-rod between the piston and cylinder composed of portions freeto slide with respect to each other, and an air-cushion formed betweenthe parts of the connecting-rod for taking up the thrust.

7. In an engine, the combination of a cylinder, a piston, a crank, aconnecting-rod between the piston and crank, composed of portions freeto slide with respect to each other, a receptacle formed in one of theparts of said connecting-rod, and a piston-like extension formed onanother of the parts and arranged to enter the receptacle, the twoconstituting an air-cushion.

8. In an engine, the combination of a twopart connecting-rod, one partbeing composed of a tubular structure, the other part being formed of arod-like structure, and the two arranged to telescope, a receptacleformed at the end of one of the parts, and a piston formed at the end ofthe other part, and arranged to enter the receptacle, the two forming adash-pot acting near the end of the independent movement of the parts ofthe con-fmeeting-rod.

IOO

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9. The combination in a vehicle, of singleacting pistons withcorresponding connecting-rods made in two sections extensible withrespect to each other, a crank and crankshaft driven by theconnecting-rods, a Worm driven by the engine-shaft, a worm-gear, anddierential gears connecting the worm-gear to the driving-wheels of thevehicle.

10. The combination of two oppositely-disposed cylinders, pistonstherefor acting upon a common crank-shaft, and a connecting-rod betweeneach piston and the crank which is composed of two parts that are freeto move with respect to each other when for any reason the crankshaft isdriven by extraneous means.

1l. The combination of two oppositely-disposed cylinders, pistonstherefor acting upon a common crank-shaft, a connecting-rod between eachpiston and the crank which is composed of two parts that are free tomove with respect to each other when for any reason the crank-shaft isdriven by extraneous means, means for causing a slight compression inthe end of the cylinder not receiving steam to prevent the idle pistonfrom traveling faster than the active piston, and means for taking upthe thrust when the parts of the connecting-rod move independent of eachother.

12. In an engine, the combination of oppositely-disposed cylinders,pistons therefor, a common crank, telescoping connecting-rods betweenthe pistons and the cranks, the parts of each rod being capable ofmoving independent of each other after the manner of a piston andcylinder, and means for breaking the vacuum which would otherwise beformed when one part moved upon the other.

13. In a vehicle, the combination of a single-acting engine, acrank-shaft geared to the wheels of the vehicle through suitablegearing, and an extensible connecting-rod which forms the onlyconnecting medium between the piston and the crank-shaft.

14. In a vehicle, the combination of a single-acting engine having acylinder and piston, a connecting-rod between the piston and the crank,said connecting-rod being extensible for the purpose described, and areducinggearing between the engine-shaft and the vehicle-wheels.

15. In a vehicle, the combination of a steam or compressed-air enginehaving single-acting pistons and cylinders, extensible connecting-4 rodsthe parts of which are free to move with respect to each other, a wormmounted upon the shaft of the engine, and a worm-gear connected with thevehicle-wheels.

' In witness whereof I have hereunto set my hand this 13th day ofNovember, 1900.

ELIHU THOMSON.

Witnesses:

DUGALD MoKILLoP, HENRY O. WESTENDARP.

